Safety lock

ABSTRACT

An improved safety lock which includes two pivotally connected members each having a shank portion with an aperture therein and a hook portion. The shank portions of the pivoted members are adapted to overlap with the apertures therein being placed in registry so as to receive the hasp of a padlock. With the shank portions of the members overlapping and the holes therein placed in registry, the free end parts of the hook portions overlap to define, in association with the remainder of the hook portions, a continuous lock ring which is adapted to extend through an anchoring aperture and around a lever or handle of a switch or valve in order to prevent the actuation of the switch or valve. The overlapping end parts of the lock&#39;&#39;s hook portions include components which cause the end parts to interlock so as to prevent the hook portions from being separated and disengaged from the switch or valve without the release of the padlock which extends through the shank portions of the safety lock and which normally prevents separating movement of the hook portions.

[54] SAFETY LOCK [72] Inventors: Albert K. Reque, Warsaw, Ind.; JuliusT.

Peterson, Chicago, Ill.

[73] Assignee: Engineering Development Co., Inc., Warsaw, Ind.

[22] Filed: Aug. 5, 1970 [21] Appl. No.1 61,246

[56] References Cited UNITED STATES PATENTS 3/1912 Tingley ..70 191,197,020 9/1916 Farrar..... 2,560,624 7 1951 Bartlett... 2,963,895l2/l960 FOREIGN PATENTS OR APPLICATIONS 489,155 7/l938 Great Britain..70/I9 [451 June 6, 1972 Primary ExaminerGeorge F. Mautz AssistantExaminer-Edward J. McCarthy Attorney-Oltsch & Knoblock [57] ABSTRACT Animproved safety lock which includes two pivotally connected members eachhaving a shank portion with an aperture therein and a hook portion. Theshank portions of the pivoted members are adapted to overlap with theapertures therein being placed in registry so as to receive the hasp ofa padlock. With the shank portions of the members overlapping and theholes therein placed in registry, the free end parts of the hookportions overlap to define, in association with the remainder of thehook portions, a continuous lock ring which is adapted to extend throughan anchoring aperture and around a lever or handle of a switch or valvein order to prevent the actuation of the switch or valve. Theoverlapping end parts of the lock's hook portions include componentswhich cause the end parts to interlock so as to prevent the hookportions from being separated and disengaged from the switch or valvewithout the release of the padlock which extends through the shankportions of the safety lock and which normally prevents separatingmovement of the hook portions.

3 Claims, 8 Drawing Figures PATENTEDJUH 8 I972 I NVEN'I ORS (JUL/US 7'.PETERSON ALBERT A. REG);

ATTORNEYS SAFETY LOCK SUMMARY OF THE INVENTION This invention relates toa safety lock for preventing actuation of a valve, switch or similarcontrol device and for preventing access to control elements within acontainer such as a switch or fuse box.

Safety locks, as illustrated in U. S. Pat. No. 2,560,624 and granted in1951, provide a margin of safety for maintenance personnel, machineoperators and electricians, and have been known and used for many years.Prior art devices of this nature generally comprise two pivotal membershaving overlapping hook portions which are used to engage the actuatingmember of a valve, switch or similar control device to prevent actuationof the control device until the safety lock is removed. Such removal ofthe safety lock is intended to be prevented until the last of one ormore padlocks which prevent pivotal movement of the hook portions areremoved from the lock so as to allow the hook portions thereof to beseparated and disengaged from the actuating lever of the control device.In actual practice, however, it has been possible to forceably separatethe hook portions of the safety lock so as to free the actuating leverof the control device without having to remove all of the padlocks fromthe lock. In this invention, the hook portions of the safety lockinclude interlocking parts which prevent forceable separation of thehook portions until the last padlock is removed from the lock.

Accordingly, it is an object of this invention to provide a safety lockfor preventing actuation of a control device, such as switches andvalves, in which means is provided for preventing the forceful removalof the lock from the control device until the lock can be safely removedby authorized personnel.

Another object of this invention is to provide a safety lock forpreventing actuation of a control device which is of economicalconstruction and of high reliability.

Other objects of this invention will become apparent upon a reading ofthe inventions description.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of oneembodiment of the safety lock of this invention shown with the hookportions thereof closed.

FIG. 2 is a perspective view of the safety lock of FIG. 1 shown with thehook portions thereof opened.

FIG. 3 is a side view of the safety lock of FIG. 1.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3.

FIG. 5 is a fragmentary side view of the closed hook portions of thesafety lock of FIG. 1 shown in modified form.

FIG. 6 is a sectional view taken along line 66 of FIG. 5.

FIG. 7 is a fragmentary side view of the closed hook portions of thesafety lock of FIG. 1 shown in another modified form.

FIG. 8 is a fragmentary view as seen from line 8-8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodimentsillustrated are not intended to be exhaustive or to limit the inventionto the precise forms disclosed. They are chosen and described in orderto best explain the principles of the invention and its application andpractical use to thereby enable others skilled in the art to bestutilize the invention.

Referring to FIGS. 1-4, the embodiment illustrated therein includes apair of lock members 10. Each lock member 10 is preferably formed of acase-hardened steel and includes a hook portion 12 and a shank portion14. Each hook portion 12 includes an end part and a concave part 22.Each shank portion 14 preferably includes a plurality of selectivelypositioned holes 16. Lock members 10 are pivotally connected by a rivet18 or other suitable fastening means so that the shank portions 14thereof can be made to overlap with each hole 16 in one shank portionregistering with a corresponding hole l6 in the other shank portion.When corresponding holes 16 in shank portions 14 are caused to register,the end parts 20 of the hook portions 12 overlap with concave parts 22thereof facing one another and cooperating to define a continuous lockring, as shown in FIGS. 1 and 3.

The hook portion 12 of each lock member 10 preferably includes acomponent, such as a tab 24, which is spaced inwardly from thetip 26 ofthe hook portion and which is bent over and spaced from the overlappedside 13 of the hook portion so as to form an opening 25 which receivesthe end part 20 of the opposite hook portion when the holes 16 in shankportions 14 are caused to register. With each end part 20 so receivedbetween a tab 24 and connected hook portion 12, the hook portions 12 ofthe safety lock cannot be laterally separated. In certain embodiments ofthis invention, it is contemplated that only one of the two hookportions 12 need carry an interlock tab 24.

FIGS. 5 and 6 are illustrative of a modification to the safety lockabove described and illustrated in FIGS. 1-4. The hook portion 12 ofeach lock member includes a pair of confronting tabs 24' which extendfrom edges 28 and 30 of the hook portion and spacedly overlie theoverlapped-side 13 of the hook portion. Tabs 24 cooperate to form anopening 25 which receives the end part 20 of the opposite hook portion.Although it is preferable for each hook portion 12 to carry tabs 24', asingle pair of the tabs carried by only one of the two hook portionswould be sufficient in many applications of this invention to providethe hook portion interlock.

In FIGS. 7 and 8, the end parts 20 of the hook portions 12 of the'safety lock illustrated in FIGS. l-4 are modified by eliminating thetabs 24 and by splitting one end part 20 at its tip 26 so as to provideinner and outer elements 32. One element 32 is preferably bent outwardlyand parallel to the plane of overlapped side 13 of the integral hookportion so as to provide an opening 34 into which the other end part 20is received as the shank portions 14 of the modified safety lock overlapand holes 16 therein are'aligned so as to receive the hasp of one ormore padlocks.

The safety lock of this invention may be utilized by inserting the hookportions 12 of the lock through an anchoring means, such as an aperturein a switch housing, and around the actuating lever of the switch, andthen closing the hook portions by pivotally moving the shank portions 14until the holes 16 therein register. The hasps of one or more padlocks,each belonging to an individual workman, are then inserted throughregistering holes 16 and locked. I

It is to be understood that the scope of this invention is to extend tothose similarly designed safety locks having pivotally connected shankswith a hook portion at each end of the shanks. Additionally, thecontinuous lock ring formed by the overlapping hook portions 12 need notbe circular but can be oval, square, rectangular, or some other shape.The apertures in the shank portions 14 need not be limited to aplurality of corresponding holes 16 but may consist of two correspondingelongated openings.

It is to be understood that the invention herein described is not to belimited to the details herein given but may be modified within the scopeof the appended claims.

What we claim is:

1. A safety lock including a pair of pivotally connected members eachhaving a shank portion and a hook portion,

each shank portion having at least one aperture therein, the shankportions being positionable in an overlapping relationship in which theapertures in the shank portions are brought into registry, each hookportion including a concave part and an end part, the concave part ofone hook portion confronting the concave part of the other hook portionwith the end parts tabs and overlapped part, each pair of tabs beinginwardly spaced from the tip of their hook portion, each hook portionend part being received in the opening formed by and between said tabsand overlapped part of the other hook portion when said shank portionsare positioned in said overlapping relationship. I

2. A safety lock including a pair of pivotally connected members eachhaving a shank portion and a hook portion, each shank portion having atleast one aperture therein, the shank portions being positionable in anoverlapping relationship in which the apertures in the shank portionsare brought into registry, each hook portion including a concave partand an end part, the concave part of one hook portion confronting theconcave part of the other hook portion with the end parts of the hookportions overlapping to define a lock ring when said shank portions arepositioned in said overlapping relationship, the improvement wherein theend part of said one hook portion includes a pair of confronting tabsextending from opposite edges of and bent over and spaced from theoverlapped part of said one hook portion defining an opening said shankportions are positioned in said overlapping relabetween said tabs andsaid overlapped part, the end part of said other hook portion beingreceived within said opening tionship.

3. A safety lock including a pair of pivotally connected members eachhaving a shank portion and a hook portion, each shank portion having atleast one aperture therein, the shank portions being positionable in anoverlapping relationship in which the apertures in the shank portionsare brought into registry, each hook portion including a concave partand an end part, the concave part of one hook portion confronting theconcave part of the other hook portion with the end parts of the hookportions overlapping to define a lock ring when said shank portions arepositioned in said overlapping relationship, the improvement wherein onehook portion end part is split at its tip and at least partially alongthe length thereof to form first and second elements, said first elementbeing offset from said said second element to define an openingtherebetween, the other hook portion end part being received within saidopening and positioned between said first and second elements when saidshank portions are positioned in said overlapping relationship. v

1. A safety lock including a pair of pivotally connected members eachhaving a shank portion and a hook portion, each shank portion having atleast one aperture therein, the shank portions being positionable in anoverlapping relationship in which the apertures in the shank portionsare brought into registry, each hook portion including a concave partand an end part, the concave part of one hook portion confronting theconcave part of the other hook portion with the end parts of the hookportions overlapping to define a lock ring when said shank portions arepositioned in said overlapping relationship, the improvement whereineach hook portion end part includes a pair of confronting tabs extendingfrom opposite edges of and bent over and spaced from the overlapped partof their hook portion defining an opening between said tabs andoverlapped part, each pair of tabs being inwardly spaced from the tip oftheir hook portion, each hook portion end part being received in theopening formed by and between said tabs and overlapped part of the otherhook portion when said shank portions are positioned in said overlappingrelationship.
 2. A safety lock including a pair of pivotally connectedmembers each having a shank portion and a hook portion, each shankportion having at least one aperture therein, the shank portions beingpositionable in an overlapping relationship in which the apertures inthe shank portions are brought into registry, each hook portionincluding a concave part and an end part, the concave part of one hookportion confronting the concave part of the other hook portion with theend parts of the hook portions overlapping to define a lock ring whensaid shank portions are positioned in said overlapping relationship, theimprovement wherein the end part of said one hook portion includes apair of confronting tabs extending from opposite edges of and bent overand spaced from the overlapped part of said one hook portion defining anopening between said tabs and said overlapped part, the end part of saidother hook portion being received within said opening and positionedbetween said tabs and overlapped part when said shank portions arepositioned in said overlapping relationship.
 3. A safety lock includinga pair of pivotally connected members each having a shank portion and ahook portion, each shank portion having at least one aperture therein,the shank portions being positionable in an overlapping relationship inwhich the apertures in the shank portions are brought into registry,each hook portion including a concave part and an end part, the concavepart of one hook portion confronting the concave part of the other hookportion with the end parts of the hook portions overlapping to define alock ring when said shank portions are positioned in said overlappingrelationship, the improvement wherein one hook portion end part is splitat its tip and at least partially along the length thereof to form firstand second elements, said first element being offset from said saidsecond element to define an opening therebetween, the other hook portionend part beIng received within said opening and positioned between saidfirst and second elements when said shank portions are positioned insaid overlapping relationship.